In recent years, various automatic switching devices have been marketed, which function to switch lighting on and off, depending on some sensed condition. For example, an ambient light level sensor may be incorporated into the switching device so as to switch on the light when the ambient light falls below a certain level (e.g. when night falls). Alternatively, there may be a motion sensor for detecting motion within a particular field of view of the detector and switching the light on when motion is detected.
One known motion detector arrangement for switching lighting has a housing which must be fixed in place (e.g high up on an external wall) and must be wired during installation thereof so as to connect into the mains power supply. This arrangement is relatively expensive and requires installation by an electrician. Additionally, the installation is not easily moved once it is fixed in place and wired into the mains power supply.
U.S. Pat. No. 4,823,051 by Young describes an infra-red actuated control switch assembly. This assembly has a motion detecting capability and is housed within a plug and socket adaptor to be interposed between a light bulb and a socket in normal domestic applications. The sensing system described by Young has a 360° range in the horizontal plane, with two separate sensing fields in a vertical field of view. This arrangement does not, however, allow for the field of view of the motion sensor to be directionally targeted. Thus, in situations where it is not desired to switch the light based on motion in a certain part of the room, the light will nonetheless be undesirably switched on. Thus, the 360° range of the assembly described by Young lacks directional adjustability and may inconveniently switch on when not desired.
It is desired to provide an adaptor device which is relatively inexpensive, easy to install and remove and has a motion sensing capability which can be directionally targeted, or to at least provide a useful alternative to the prior art.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.